Engines, such as those which power aircraft and industrial equipment, may employ a compressor to compress air that is drawn into the engine and a turbine to capture energy associated with the combustion of a fuel-air mixture. The captured energy causes a rotor of the turbine to rotate, which in turn causes a rotor of the compressor to rotate based on one or more shafts that connect the turbine and the compressor. The shaft(s) are supported by bearings that are contained within a bearing compartment. A lubrication system supplies lubricant to the bearings in order to clean, cool, and lubricate the bearings.
As an example of the foregoing, and referring to FIG. 1A, a turbine engine shaft 10′ is shown that is supported from a non-rotatable structure of the engine by bearings 12′ so that the shaft 10′ is rotatable about a centerline axis 14′. The bearings 12′ are enclosed in a bearing compartment 16′ bounded by a compartment housing 18′ and by the shaft 10′. Seals 20′ segregate the compartment from its immediate surroundings. These seals 20′ are imperfect; i.e., the seals 20′ allow some leakage despite being designed and manufactured according to exacting standards.
A lubrication system 22′ includes a lubricant supply subsystem 24′. The lubricant supply subsystem 24′ includes a pump, an oil tank, supply lines, and other components not illustrated. The supply subsystem 24′ introduces oil into the bearing compartment 16′. The lubrication system 22′ includes a deoiler 26′, which is typically enclosed inside an engine gearbox 28′. The lubrication system 22′ includes a buffering subsystem 30′, which extracts pressurized air, referred to as buffer air, from a working medium flowpath of the engine and delivers it to the vicinity of the seals 20′ outside the bearing compartment 16′. The pressure of the buffer air exceeds the prevailing pressure inside the bearing compartment 16′, thus establishing a positive pressure difference across the seals 20′.
During engine operation, the oil cools and lubricates the bearings 12′. The positive pressure difference across the seals 20′ causes buffer air to flow past the seals 20′ and into the compartment 16′ to help prevent oil from leaking past the seals 20′ in the opposite direction. The air and oil cross-contaminate each other in the compartment 16′. The oil-contaminated air, referred to as breather air, flows out of the compartment 16′ to the deoiler 26′ and is replenished by fresh buffer air flowing past the compartment seals 20′. The deoiler 26′ separates the oil from the air, vents the decontaminated air overboard, and discharges the separated oil to the oil pump.
Conventionally, the deoiler 26′ includes a large number of components to facilitate the functionality of the deoiler 26′ over the operating profile of an engine—see, for example, U.S. Pat. No. 7,377,110 for a description/illustration of a deoiler. The contents of U.S. Pat. No. 7,377,110 are incorporated herein by reference. A reduction in the number of components used in a deoiler would: (1) increase the reliability of the deoiler, (2) decrease the cost of the deoiler, and (3) reduce the weight of the deoiler.